OBJECTIVE: The key factors that promote the termination of focal seizures have not been fully clarified. The buildup of neuronal synchronization during seizures has been proposed as one of the possible activity-dependent, self-limiting mechanisms. We investigate if increased thalamo-cortical coupling contributes to enhance synchronization during the late phase of focal seizure-like events (SLEs) generated in limbic regions.

METHODS: Recordings were simultaneously performed in the nucleus reuniens of the thalamus, in the hippocampus and in the entorhinal cortex of the isolated guinea pig brain during focal bicuculline-induced SLEs with low voltage fast activity at onset.

RESULTS: Spectral coherence and cross-correlation analysis demonstrated a progressive thalamo-cortical entrainment and synchronization in the generation of bursting activity that characterizes the final part of SLEs. The hippocampus is the first activated structure at the beginning of SLE bursting phase and thalamo-hippocampal synchronization is progressively enhanced as SLE develops. The thalamus takes the lead in generating the bursting discharge as SLE end approaches.

SIGNIFICANCE: As suggested by clinical studies performed during pre-surgical intracranial monitoring, this data confirms a role of the midline thalamus in leading the synchronous bursting activity at the end of focal seizures in the mesial temporal regions.

Related News

January 17, 2019

Prevalence and Trajectories of Depressive Symptoms Among Mothers of Children with Newly Diagnosed Epilepsy: A Longitudinal 10-Year Study

A substantial proportion of mothers of children with epilepsy are at risk for depression, and this risk is stable over the long term.

January 17, 2019

Noninvasive Tests Help ID Seizure Site in Children with Focal Epilepsy

Naming tasks, which have helped to localize and lateralize a seizure onset region for surgery of focal epilepsy in adults, could now be as useful in children, with the recently reported success of a novel, age-specific assessment.